The invention relates to an arrangement of a measurement controlling device in circular grinding machines with a loading arrangement or an automatic workpiece shifting arrangement, which operates on the double-point measuring principle and is equipped with a liftable operator key, especially for measuring tracks of roller bearing rings of a variety of embodiments or other ring-shaped workpieces during their machining.
The ever-increasing quality requirements during recent years concerning precision of the geometrical shape of the tracks of roller bearings rings of a variety of embodiments or of other ring-shaped workpieces resulted in substitution of the previously used single-point measurement controlling devices with units which operate according to the double-point measuring principle in the corresponding circular grinding machines. The introduction of the double-point measuring heads resulted in an increased space requirement in the operating room of the machine as well as in increased time requirements since after completing each grinding process, the measuring head initially must be completely withdrawn from the operating area to make it possible to change the workpiece. The additional time required depends on the outer diameter of the workpieces. The additionally required retracting mechanism for in-and-out driving of the measuring head is arranged on the machine table so that its guiding pieces are constantly within the operating area of the machine, thus subjected to constant wear and tear. In addition, the operating room of the machine is limited by the presence of the retracting mechanism and can no longer be clearly visible. According to DE-OS No. 22 57 433, it has previously been attempted to cut the additional time requirement for driving out the measuring head. This embodiment provided that the dimension of the workpiece was compared with a predetermined value during the first step of the operating process, the dimension was no longer measured at the attainment of a predetermined relationship to the predetermined value, and thereafter, the machining of the workpiece proceeded until attainment of the finished measurement in a pre-programmed manner, at least depending upon the final measured dimensions. Here, the measuring head may be previously removed before termination of the machining period of the workpiece.
For this procedure, an additional electronic controlling circuit is necessary, which consists of a relationship circuit and a program circuit, wherein the program circuit includes a differentiator and is connected to a memory storage and to a signalling generator.
The disadvantage in this embodiment is that additional electronic controlling is necessary. Additionally, the grinding process cannot be controlled until the required measurement is attained, which could result in a lowering of quality. Furthermore, a retracting mechanism for the measuring head is necessary.
The object of the invention is to create conditions under which the advantages of the double-point measuring principle can be used and the previously mentioned disadvantages can be avoided.
The task of the invention is to create an advantageous arrangement for a measurement controlling device which operates according to the double-point measuring system for circular grinding machines which does not require additional electronic controlling and additional time for driving out the measuring head, ensuring excellent quality of measurement controlled grinding until attainment of the prescribed measurement. Moreover, the operating location of the machine should not be limited and no equipment which is subject to constant wear and tear by arrangement in the operating room should be employed. The operating capacity of the machine should not be restricted herein in any way.